Driving mechanisms for timepieces have been disclosed. For example, European patent application EP 1406131 A1 describes a timepiece mechanism adapted to drive successive instantaneous jumps of disks showing the current hour and minute. This mechanism includes, for each of the two time units to be displayed, a mobile comprising a driving wheel and a cam coaxial with this wheel and having a periphery of varying radius, to be more precise of sawtooth shape. The cam is constrained to rotate with the driving wheel, the latter being driven from a finishing wheel. A pivoting lever is arranged to cooperate on the one hand with the cam, via a nose, and, on the other hand, with a counter of the corresponding time unit, via a lever carrying a pawl with which it meshes.
Spring means are provided for pressing the nose against the periphery of the cam at all times; the lever therefore pivots when the nose follows the rising profile of a sawtooth of the cam, before falling when the nose is facing the radial face of the same tooth. The nose falling, and therefore the lever returning to its position nearest the cam, leads to instantaneous incrementing of the counter of the corresponding time unit.
However, in the description of the above EP application, the applicant acknowledges a drawback of this type of mechanism, namely the fact that the cam can be driven in only one rotation direction, given the orientation of its teeth. Accordingly, this document provides a device for correction of the current time adapted to prevent any rotation of the cam in the wrong rotation direction. To be more precise, this correction device enables the current time to be modified without using the levers.
The use of such a correction device is nevertheless not always desirable, in particular if the information to be displayed has a greater number of possible values, for example the date. It will also be noted that the display of some information, such as the date, for example, is generally controlled by the same means as control the display of the current time. In this case, manual correction of the current time may damage the mechanism for instantaneously driving this information.
European patent EP 1918792 B1 describes a corrector mechanism associated with a similar driving mechanism enabling both forward and backward correction of the value of a time indication. To this end, this corrector mechanism includes a return lever arranged in the same plane in the vicinity of the lever cooperating with the cam to control the display of the time indication to raise the lever by means of a setting wheel and to move its nose out of reach of the periphery of the cam when a backward correction is made.